TM-AFM

Figure 8.4. TM-AFM images of SILAR-grown ZnS on (100)Si after (a) 0, (b) 2, (c) 5, (d) 10, (e) 20, (f) 50, and (g) 100 cycles. Depth scale lOnm (a)-(c), 25nm (d)-(f), and 75 nm (g) from black to white. Reprinted from Valkonen, Lindroos, Resch, Leskela, Friedbacher and Grasserbauer. 1998. Applied Surface Science 136, Copyright (1998) with permission from Elsevier.

Resch, R. Friedbacher, G. Grasserbauer, M. Kanniainen, T. Lindroos, S. Leskela, M. Niinisto, L. 1997. In situ investigations on the SILAR-growth of ZnS films as studied by tapping mode atomic force microscopy (TM-AFM). Fresenius J. Anal. Chem. 358 80-84. 

TCLP TDB TDF THC TBP TEM TLM TM-AFM TOC TRLFS TRU TSP TST TVS Toxicity characteristics leaching procedure Thermodynamic database Tyre-derived fuel Total hydrocarbon Tri-n-butyl phosphate Transmission electron microscopy Triple layer model Tapping mode atomic force microscopy Total organic carbon Time-resolved laser fluorescence spectroscopy Transuranic Total suspended particles Transition state theory Transportable vitrification system... 

Analysis of the TM-AFM data demonstrates that there is a good correlation (<20% difference) between the experimentally determined and calculated parameters for four of the five nanostructures (Table 4.1). The best correlation was found for assemblies [l3 (DEB)6]n (< 10%), which is the result of a most densely packed structure. It is remarkable that in the case of assembly [la3 6a3]n, the only one that is formed from the polar solvent DMSO, exhibits a significant distance between nanorods (n = 1.5). The value suggests that the nature of the solvent plays an important role. 

TABLE 4.1. TM-AFM Data for the Hydrogen-Bonded Rodlike Nanostructures. 

Fig. 30 TM-AFM phase images of PEOpy-49 films with various thicknesses on oxidized silicon a 2.5 im, b 110 nm, and c 15 nm [72]...

Fig. 2.11 Scope traces for TM-AFM height and amplitude images recorded for different gain settings (details see text)...

Fig. 2.21 Amplitude A (curve with maximum) and phase response of TM-AFM cantilever...

Fig. 2.34 TM-AFM height images displaying (a) vibration noise due to insufficient vibration isolation and (b) horizontal spikes due to external shocks that were not damped by the isolation system. In panel (c) an upscan with six different velocities is displayed...

Fig. 2.38 (a) TM-AFM height image of block copolymer and calculated Rq and RA roughness values. The displayed numbers (output of software) possess an unjustified number of decimals, (b) Schematic of two surface profiles that exhibit identical Rq and RA, yet widely different feature size... 

Fig. 2.42 (a) Model to quantitatively describe the effect of tip broadening (b) TM AFM height image of dendrimers while the diameter of dendrimers in solution was determined to be 3.5 nm the dimension of each dot are height 0.9 0.2 nm, width 23 4 nm). Reproduced with permission from [32], Copyright 2000. American Chemical Society... 

Fig. 2.46 TM-AFM images of the same area of a vertically stretched elastomeric polypropylene as imaged (a) with a fresh and (b) with an aged tip [33]...

Fig. 2.47 TM-AFM image of a PEO crystal in a melt of PEO. Because of an imaging artefact the crystal appears to be located at a lower depth (Reproduced with permission from [34], Copyright 2003. American Chemical Society)...

Fig. 2.48 Scope traces (TM-AFM) with high (upper panel) and too low (middle panel) gains. The mounting angle of the AFM cantilever and the inclination angle of the tip on the cantilever determine the possibility to image steep features, as shown for a silicon nitride CM AFM probe in the bottom panel (reproduced with kind permission from the Veeco user manual). As a result of this, the tip s interaction with sidewalls may depend on the direction...

Fig. 2.49 Overview on artefacts in TM-AFM (a) TM AFM height image of a scan during which the tip temporarily lost contact with the sample surface (setpoint free oscillation amplitude) panel (b) displays the bistability effect in intermittent contact mode AFM...

Fig. 3.10 Structure of dendrimers inserted in a self-assembled monolayer on Au(lll) (left) and TM-AFM height image acquired in air (z-scale 3 nm). Reproduced with permission from [24]...

Fig. 3.11 TM-AFM height image of a PIC-Ni sample. Film prepared from a chloroform solution containing (a) 0.01 and (b) 0.001 g/L of PIC-Ni. White arrows indicate intersections of separate chains and black ones mark segments consisting of intercoiled chains. Z range h = 2 nm. Reproduced with permission from [25]. Copyright 2002. American Chemical Society...

Fig. 3.12 TM-AFM height (400 x 400 nm2) (a) and phase contrast (b) pictures acquired simultaneously on 150 kD PEI adsorbed onto mica. The z range in the height image is 2 nm, and the range of phase shifts is 5°. The insets in a and b show corresponding height and phase images of mica incubated with 1 mM KC1 buffered at pH 4 but without polymer. Reproduced with permission from [26]. Copyright 1999. American Chemical Society...

The TM-AFM set up and procedure do not differ from the details discussed above in hands-on example 1 (Standard tapping intermittent contact mode set-up). Care must be taken to operate the AFM with a, minimum free amplitude (A0) in order to minimize the flattening of the observed macromolecules due to the interaction with the probe tip. 

Imaging of the Surface Morphology of Poly(ethylene terephthalate) (PET) by TM-AFM... 

Fig. 3.17 TM-AFM height image of PET quenched from the melt to liquid nitrogen temperature (left) and sample crystallized isothermally at 190°C for 10 min (z range 14 nm) [42]...

A TM-AFM scan of amorphous PET is shown in Fig. 3.17 A in comparison to an isothermally crystallized sample. On the rather smooth surface of the glassy PET, some undulations can be seen. The roughness analysis carried out over the shown scan size of 1.00 x 1.00 pm2 leads to an rms roughness of 0.9 nm (compared to 9.3 nm for the crystallized sample). This former value compares well with rms roughnesses measured on annealed glass or Si wafers (rms roughness 0.5 nm). 

This amorphous sample can be oriented and partially crystallized by uniaxial extension (see Fig. 3.26 for AFM images of the crystal structure of PET at the surface of the observed microfibrils). In contrast to TM-AFM, the surface of the amorphous PET film is modified by CM-AFM, similar to the example of PS discussed above. This observation confirms that CM-AFM imaging of amorphous polymers is not recommended. 

TM-AFM Visualization of Dewetted Drops of Fomblin ZDOL on a HD Surface... 

Fig. 3.18 TM-AFM height image (left) and cross-section analysis (right) of drop of dewetted Fomblin ZDOL on a hard disc surface [44]...

In general, it is possible to visualize individual solution-grown lamellae by both CM-AFM and TM-AFM. The same is true for many melt-grown lamellae. Due to the contrast based on the difference in energy dissipation between amorphous and crystalline phases in the TM-AFM phase images, the lamellae can be seen with excellent contrast, and hence, high resolution. Two examples of lamellae of poly (ethylene oxide) (PEO) viewed in flat-on and edge-on projection are shown in Fig. 3.19. 

Imaging of iPP Lamellae in iPP by TM-AFM Phase Imaging and Pulsed Force Mode... 

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